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Order Ceramiales

Family Rhodomelaceae

Laurencia complanata (Suhr) Kützing 1849: 857

Plants red to dark red, epilithic, complanate, up to about 20 cm tall. Holdfast discoidal, bearing several pyramidal axes, axes 3-4 mm wide, pinnately branched in up to 4 orders. Branches closely spaced, equal lengths on each side of axes. Terminal branches short (0.5-1 mm long), truncated. In cross section central (axial) cell and four (indistinct) pericentral cells. Medullary cells becoming smaller outwards, often with thickened cell walls (lenticular thickening); single layer of cortical cells, 40-50 um high. Tetrasporangia borne in terminal branchlets, 130-150 um in diameter, division tetrahedral. Sexual structures not seen.

Collections, ecology and regional distribution

Recorded from Hluleka eastwards to northern KwaZulu-Natal (45-58). Found in rock pools and the shallow subtidal zone.

Word distribution: Also reported from Mozambique (De Clerck et al. 2005).

Type locality: Durban, KwaZulu-Natal, South Africa (De Clerck et al. 2005).

Note: A DNA study of South African Laurencia supported this as a valid species (Francis et al. 2017).


Laurencia complanata, frond detail.

Laurencia complanata, cross section showing cortex and some of medulla.

Laurencia complanata, cross section showing secondary pit connections between outer medullary cells.


References Laurencia complanata

De Clerck, O., Tronchin, E. M., & Schils, T. 2005. Red algae. In: De Clerck, O., J.J. Bolton, R. J. Anderson and E. Coppejans, 2005. Guide to the Seaweeds of Kwazulu-Natal. National Botanic Garden of Belgium, Brussels (Scripta Botanica Belgica), pp. 130-269.

Francis, C.M., Bolton, J.J., Mattio, L., Mandiwana-Neudani, T. & Anderson, R.J. 2017. Molecular systematics reveals increased diversity within the South African Laurencia complex (Rhodomelaceae, Rhodophyta). Journal of Phycology. 53: 804-819.


Cite this record as:

Anderson RJ, Stegenga H, Bolton JJ. 2016. Seaweeds of the South African South Coast.
World Wide Web electronic publication, University of Cape Town,; Accessed on 26 February 2024.